3 years ago

6.3c-2(1.5c+4.1) simplify

Mathematics

1 answer:

svp [43]3 years ago

7 0

6.3c-2(1.5c+4.1)=6.3c-3c-8.2=3.3c-8.2 :))))

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5x + 6y = 20 , 8x - 6y = -46

serg [7]

Answer:

5x + 6y = 20_____(1)

8x - 6y = -46_____(2)

Solving simultaneously:

Eqn(1) + Eqn(2)

5x + 8x + 6y + (-6y) = 20 + (-46)

13x = -26

x = -2

substituting this into Eqn (1):

5(-2) + 6y = 20

-10 + 6y = 20

6y = 30

y = 5

hence:

x = -2,y = 5.

7 0

3 years ago

Find the z-scores for which 8% of the distribution's area lies between minus−z and z.

Troyanec [42]

$\mathbb P(-z$

Because the distribution (normal) is symmetric, you know that $\mathbb P(Zz)$ , so

$\mathbb P(Zz)=2\mathbb P(Z$

Now,

$\mathbb P(-z$
$\implies\mathbb P(Z$

If $F_Z(z)$ is the CDF of the normal distribution, so that $F_Z(z)=\mathbb P(Z$ , then the z-score satisfies

$\begin{cases}z={F_Z}^{-1}(0.54)\\z=-{F_Z}^{-1}(0.46)\end{cases}$

so that $z\approx0.1004$ .